U.S. patent application number 17/017908 was filed with the patent office on 2021-03-18 for automatic pallet changer in machine tool.
This patent application is currently assigned to OKUMA CORPORATION. The applicant listed for this patent is OKUMA CORPORATION. Invention is credited to Makoto Yoshida.
Application Number | 20210078124 17/017908 |
Document ID | / |
Family ID | 1000005108062 |
Filed Date | 2021-03-18 |
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United States Patent
Application |
20210078124 |
Kind Code |
A1 |
Yoshida; Makoto |
March 18, 2021 |
AUTOMATIC PALLET CHANGER IN MACHINE TOOL
Abstract
Provided is an automated pallet changer in machine tool which
enable miniaturization and cost reduction. A drive unit in the
automatic pallet changer includes a planetary reduction gear. The
planetary reduction gear has a first output shaft and a second
output shaft in which, by fixing one of the first and second output
shaft, the other functions as an output shaft for driving. The
first output shaft is used to pivot the pivoting frame, and the
second output shaft is used to move the carry-in/out arm back and
forth.
Inventors: |
Yoshida; Makoto; (Niwa-gun,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OKUMA CORPORATION |
Niwa-gun |
|
JP |
|
|
Assignee: |
OKUMA CORPORATION
Niwa-gun
JP
|
Family ID: |
1000005108062 |
Appl. No.: |
17/017908 |
Filed: |
September 11, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23Q 7/1468 20130101;
B23Q 7/1431 20130101 |
International
Class: |
B23Q 7/14 20060101
B23Q007/14 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 13, 2019 |
JP |
2019-167466 |
Claims
1. An automatic pallet changer in machine tool, comprising: a
pallet storage section for storing pallets in multiple rows and
multiple stages; a carry-in/out arm that supports the pallet and
moves in back and forth direction for carrying in/out the pallet
to/from the pallet storage section; a horizontal movement frame
that moves horizontally for moving the carry-in/out arm to a front
of a predetermined row of the pallet storage section; a lifting
frame that moves in up and down direction for moving the
carry-in/out arm to a front of a predetermined stage of the pallet
storage section; and a drive unit for driving the carry-in/out arm,
the horizontal movement frame, and the lifting frame, wherein the
drive unit includes a planetary reduction gear having a first
output shaft and a second output shaft in which, by fixing one of
the first and second output shafts, the other functions as the
output shaft for driving, each of the first and second output
shafts has axis in up and down direction, and one of the first and
second output shafts is used to move the horizontal movement frame
horizontally and the other is used to move the carry-in/out arm in
back and forth direction.
2. The automatic pallet changer in machine tool according to claim
1, wherein a first rotating gear fixed to the first output shaft of
the planetary reduction gear is configured to move integrally with
the horizontal movement frame and engaged with a fixed gear or a
rack fixed to a base frame, and, when the first rotating gear
rotates, the first rotating gear and the horizontal movement frame
move horizontally integrally.
3. The automatic pallet changer in machine tool according to claim
1, wherein a second rotating gear fixed to a second output shaft of
a planetary reduction gear is engaged with a third rotating gear
fixed to a spline shaft having an axes in up and down direction, a
pinion gear is integrally disposed at the outer circumference of a
spline nut fitted to the spline shaft, a rack engaged to the pinion
gear and extending in back and forth direction is fixed to the
carry-in/out arm, and when the second rotating gear rotates, the
third rotating gear, the spline shaft, the spline nut and the
pinion gear rotate integrally, so that the rack and the
carry-in/out arm move in back and forth direction integrally.
4. The automatic pallet changer in machine tool according to claim
1, wherein a means for fixing the first output shaft is formed by a
piston horizontally movably supported to a cylinder fixed to the
horizontal movement frame and a piston inlet hole provided in a
block fixed to the base frame into which a distal end portion of
the piston is fitted.
5. The automatic pallet changer in machine tool according to claim
1, wherein a means for fixing the second output shaft is formed by
a piston movably supported in up and down direction to a cylinder
fixed to a casing for supporting a planetary reduction gear and a
piston inlet hole provided in the second rotating gear into which a
distal end portion of the piston is fitted.
Description
TECHNICAL FIELD
[0001] The present invention relates, for example, to an automatic
pallet changer in a machine tool such as a machining center.
BACKGROUND ART
[0002] Machine tools, such as machining centers, are known to use
pallets for mounting and supplying workpieces, and to use automatic
pallet changers (APCs) for automatically replacing pallets with
workpieces.
[0003] The automatic pallet changer is known not only to store the
pallet in a planar manner, but also to be a three-dimensional APC
in which the pallet can be stored in a three-dimensional manner
(Patent Document 1).
[0004] In a three-dimensional automatic pallet changer, as a
configuration for carrying in/out the required pallet to/from a
pallet storage section to store pallets in a plurality of rows and
stages, it is essential to have a carry-in/out arm that supports
the pallet and carries in/out the pallet to/from the pallet storage
section, a pivoting frame that moves in a horizontal direction to
move the carry-in/out arm to a front of a predetermined row of the
pallet storage section, and a lifting frame that moves in a
vertical direction to move the carry-in/out arm to a front of a
predetermined stage of the pallet storage section.
[0005] Conventionally, the carry-in/out arm, the pivoting frame,
and the lifting frame were each driven by a different drive with a
motor respectively.
CITATION LIST
Patent Literature
[0006] Patent Literature 1: Japanese Patent Application Laid-Open
Publication No. 9-309038
SUMMARY OF INVENTION
Technical Problem
[0007] Although a three-dimensional automatic pallet changer has
the advantage of being able to improve the efficiency of machining
by the machine tool by storing a large number of pallets, there is
a problem of increasing the size of the machine and incurring
costs, and it is hoped that this problem will be solved.
[0008] An object of the present invention is to provide an
automated pallet changer for machine tools that enables
miniaturization and cost reduction.
Solution to Problem
[0009] The automatic pallet changer of the present invention
includes a pallet storage section for storing pallets in multiple
rows and multiple stages, a carry-in/out arm that supports the
pallets and moves in the back and forth direction for carrying
in/out the pallet to/from the pallet storage section, a horizontal
movement frame that moves horizontally for moving the carry-in/out
arm to a front of a predetermined row of the pallet storage
section, a lifting frame that moves in the up and down direction
for moving the carry-in/out arm to a front of a predetermined stage
of the pallet storage section, and a drive unit for driving the
carry-in/out arm, the horizontal movement frame, and the lifting
frame. In an automatic pallet changer for machine tools that carrys
the required pallet between the machine tool body and the pallet
storage section, the driving device includes a planetary reduction
gear having a first output shaft and a second output shaft in
which, by fixing one of the first and second output shafts, the
other functions as the output shaft for driving. Each of the first
and second output shafts has axis in the up and down direction. One
of the first and second output shafts is used to move the
horizontal movement frame horizontally and the other is used to
move the carry-in/out arm in the back and forth direction.
[0010] According to the automatic pallet changer in the machine
tool of the present invention, a planetary reduction gear and a
motor for driving the planetary reduction gear can be used to drive
both the horizontal movement of the horizontal movement frame and
the forward and backward movement of the carry-in/out arm, thereby
miniaturization and cost reduction, compared to the conventional
automatic pallet changer in which different motors are respectively
used to drive the horizontal movement of the horizontal movement
frame and the forward and backward movement of the carry-in/out
arm, can be achieved.
[0011] A first rotating gear fixed to the first output axis of the
planetary reduction gear is adapted to move integrally with the
horizontal movement frame and is engaged with a fixed gear or a
rack fixed to a base frame, so that when the first rotating gear
rotates, the first rotating gear and the horizontal movement frame
may move horizontally together.
[0012] A second rotating gear fixed to a second output shaft of a
planetary reduction gear is engaged with a third rotating gear
fixed to a spline shaft having an axis in the up and down
direction, a pinion gear is integrally disposed around the outer
periphery of the spline nut fitted to the spline shaft, a rack,
which is engaged to the pinion gear and extends in the back and
forth direction, is fixed to the carry-in/out arm, and when the
second rotating gear rotates, the third rotating gear, the spline
shaft, the spline nut and the pinion gear rotate integrally, and
the rack and the carry-in/out arm may move forward and backward
together.
[0013] The means for fixing the first output shaft may be formed by
a piston that is supported by the horizontal moving frame in a
horizontally movable manner and a piston inlet hole that is
provided in a block fixed to the base frame and into which the
piston tip is fitted.
[0014] Preferably, the means for fixing the second output shaft is
formed by a piston that is supported movably in the up and down
direction by a casing which supports the planetary reduction gear
and a piston inlet hole that is provided in a second rotating gear
and into which the piston tip is fitted.
Advantageous Effect of Invention
[0015] According to the automatic pallet changer in the machine
tool of the present invention, one planetary reduction gear and one
motor that drives the planetary reduction gear can be used to drive
both horizontal movement of the horizontal movement frame and
forward and backward movement of the carry-in/out arm, thereby
miniaturization and cost reduction can be achieved.
BRIEF DESCRIPTION OF DRAWINGS
[0016] FIG. 1 is a plan view illustrating an automatic pallet
changer in the machine tool of the present invention.
[0017] FIG. 2 is a elevational view illustrating an automatic
pallet changer in a machine tool of the present invention.
[0018] FIG. 3 is a cross-sectional view illustrating a device for
driving a rotating frame and an carry-in/out arm of an automatic
pallet replacement device.
[0019] FIG. 4 is a plan view enlarging the automatic pallet changer
of FIG. 1.
[0020] FIG. 5 is an elevational view enlarging the automatic pallet
changer of FIG. 1.
DESCRIPTION OF EMBODIMENTS
[0021] Hereinafter, the embodiment of the automatic pallet changer
of the present invention will be described with reference to the
drawings. In the following description, the side where the
carrying-in/out arm approaches the pallet (right side of FIG. 1) is
referred to as the front side and the side away from the pallet
(left side of FIG. 1) is referred to as the rear side, and the top
and bottom of FIG. 2 are referred to as the vertical side.
[0022] In addition, the left and right shall be from the rear to
the front.
[0023] FIGS. 1 and 2 schematically illustrate a machine tool body 1
and an automatic pallet changer 2 mounted on the front side of a
machine tool body 1.
[0024] The machine tool body 1 is a horizontal machining center
that machines a workpiece W attached to the pallet P, and includes
a pallet delivery device 3, a table 4 that moves the pallet P, and
a machining device 5 that machines the workpiece W.
[0025] The automatic pallet changer 2 is a three-dimensional type
with a pallet storage section 11 for storing the pallets P in
multiple rows in a circumferential direction and multiple stages in
a vertical direction. The pallets P is carried in/out between the
pallet storage section 11 and the machine tool body 1.
[0026] The pallet storage section 11 is formed so as to have a
C-shape in planar view.
[0027] The automatic pallet replacement device 2 includes an
carry-in/out arm 12 that supports the pallet P and carries in/out
the pallet P to/from the pallet storage portion 11, a pivoting
frame (horizontal movement frame) 13 that moves horizontally for
moving the carry-in/out arm 12 to a front of a predetermined row of
the pallet storage portion 11, a lifting frame 14 that moves in up
and down direction for moving the carry-in/out arm 12 to a front of
a predetermined stage of the pallet storage portion 11, a
pivoting/carry-in/out drive unit (horizontally moving/carry-in/out
drive unit) 15 that moves the carry-in/out arm 12 and the pivoting
frame 13, and a lifting drive unit 16 that moves the lifting frame
14.
[0028] Hereinafter, the details of the automatic pallet changer 2
will be described with reference to FIGS. 3 to 5.
[0029] The automatic pallet changer 2 includes, as a fixed portion,
a base frame 17, a pivot center shaft 18 fixed on the base frame
17, and a fixed gear 19 fixed concentrically on the pivot center
shaft 18.
[0030] The carry-in/out arm 12 consists of a pair of parallel
plates extending in the forward and backward direction, and is
supported movably in the forward and backward directions (from the
front side to the backside or from the backside to the front side
of the sheet in FIG. 3, and the left and right directions in FIGS.
4 and 5).
[0031] The pivoting frame 13 includes four longitudinal frames 13a
and a transverse frame 13b that connects the upper ends and the
lower ends of the four longitudinal frames 13a in a U shape in top
plan view.
[0032] The lifting frame 14 is nearly U-shaped and is supported
movably in the up and down direction to two longitudinal frames 13a
on the front side of the pivoting frame 13.
[0033] The carry-in/out arm 12 moves in the up and down direction
integrally with the lifting frame 14 and is movable in the up and
down direction from a position corresponding to the bottom surface
of the lowermost pallet to a position corresponding to the bottom
surface of the uppermost pallet.
[0034] The pivoting/carrying-in/out drive unit 15 is configured to
drive both the pivoting of the pivoting frame 13 and the
forward/backward movement of the carrying-in/out arm 12, and the
lifting drive unit 16 is configured to drive the lifting of the
lifting frame 14.
[0035] The pivoting/carrying-in/out drive 15 includes a planetary
reduction gear 20 having an input shaft 22 rotated by a motor 21
and a first output shaft 25 and a second output shaft 26, as shown
in FIG. 3.
[0036] The planetary reduction gear 20, which is not shown in its
internal structure, includes a solar gear, a plurality of planetary
gears engaging with the solar gear and an internal gear engaging
with the inner periphery of the planetary gears. The planetary
reduction gear 20 is a reducer configured to reduce the high speed
rotation of the motor 21 and output by the first output shaft 25 or
the second output shaft 26.
[0037] The planetary reduction gear 20 can rotate the first output
shaft 25 by preventing the second output shaft 26 from rotating by
the first fixing means 23, and the second output shaft 26 can be
rotated by preventing the first output shaft 25 from rotating by
the second fixing means 24.
[0038] The motor 21 and the planetary reduction gear 20 are
supported on casing 27, which is fixed to the pivoting frame 13 and
rotates integrally with the pivoting frame 13.
[0039] The pivoting frame 13 is supported on the pivot center shaft
18 so that it can be rotated about the axis of the pivot center
shaft 18, and can be pivoted about the axis of the pivot center
shaft 18 on the trajectory plane 17a provided on the base frame 17
via a plurality of bearings 31.
[0040] The pivoting/carrying-in/out drive unit 15 includes a
pivoting gear (the first rotating gear) 32 that engages the fixed
gear 19 and is fixed to the first output shaft 25 of the planetary
reduction gear 20 in order to rotate the rotating frame 13.
[0041] The pivoting gear 32 can pivot while rotating around the
outer circumference of the fixed gear 19 when the fixation is
released.
[0042] A guide rail 42 is fixed to the undersurface of the
carry-in/out arm 12, and the guide rail 42 is configured to move on
a guide block 41 fixed on the lifting frame 14.
[0043] A rack 43 extending in the forth and back direction is
provided on the carrying-in/out arm 12.
[0044] The pivoting/carrying-in/out drive unit 15 includes a spline
shaft driving gear (a second rotating gear) 44 having an axial line
in the up and down direction and fixed to the second output shaft
26 of the planetary reduction gear 20 in order to move the
carrying-in/out arm 12 back and forth.
[0045] A spline shaft driving gear 44 is engaged with a spline
shaft driving gear 46 fitted into and fixed to the lower end
portion of a spline shaft 45 extending in the up and down
direction.
[0046] The spline shaft 45 is rotatably supported and is provided
to extend parallel to the longitudinal frames 13a of the pivoting
frame 13 through the vicinity of the carry-in/out arm 12.
[0047] In the spline shaft 45, a spline nut 47 is movably fitted in
the up and down direction.
[0048] The spline nut 47 is integrally formed with a pinion gear 48
engaged with the rack 43 of the carry-in/out arm 12.
[0049] The spline nut 47 is fixed to the vertical portion 14a of
the lifting frame 14 via a bracket 49, and when the lifting frame
14 moves in the up and down direction, the bracket 49, the spline
nut 47, and the carry-in/out arm 12 (including the guide blocks 41,
the guide rails 42, and the rack 43) are moved integrally.
[0050] The first fixing means 23 comprises a piston 52 for carrying
in/out and driving which is supported movably in the up and down
direction to a cylinder 51 fixed to a casing 27, and a piston inlet
hole 53 which is formed in the spline shaft driving gear 44 and
into which the lower end (distal end) of the piston 52 is
fitted.
[0051] The second fixing means 24 comprises a piston 55 for
pivoting and fixing which is supported movably left-to-right to a
cylinder 54 which is fixed to a pivoting frame 13, and a block 56
which is fixed to the base frame 17 and has a piston inlet hole 56a
into which the left end (distal end) of the piston 55 is
fitted.
[0052] The lifting drive unit 16 includes a guide rail 61 fixed to
the longitudinal frames 13a of the pivoting frame 13, a rack 62
fixed to the longitudinal frames 13a of the guide rail 61 so as to
be parallel to the guide rail 61, a guide block 63 which is fixed
to the lifting frame 14 and moves along the guide rail 61, and a
pinion gear 64 which is rotatably engaged to the rack 62 and moves
in the up and down direction integrally with the lifting frame
14.
[0053] According to the lifting drive unit 16, when the pinion gear
64 is rotated by a motor which is not shown, the pinion gear 64
moves up and down along the rack 62 so that the lifting frame 14
moves up and down relative to the pivoting frame 13.
[0054] The pivoting of the pivoting frame 13 by the
pivoting/carrying-in/out drive unit 15 is performed in the
following manner.
[0055] The second output shaft 26 is fixed by the first fixing
means 23 and the first output shaft 25 is released from the
fixation by the second fixing means 24, thereby making the pivoting
gear 32 rotatable.
[0056] In this state, when the input shaft 22 is rotated by the
motor 21, the pivoting gear 32 rotates and the pivoting frame 13
pivots.
[0057] With the pivoting of the pivoting frame 13, in FIG. 3, all
components other than the fixing portions 17, 18, 19, and 56 are
pivoted together.
[0058] The back and forth movement of the carrying-in/out arm 12 by
the pivoting/carrying-in/out drive unit 15 is performed in the
following manner.
[0059] The first output shaft 25 is fixed by the second fixing
means 24 and the second output shaft 26 is released from the
fixation by the first fixing means (23), thereby making the spline
shaft drive gear 44 rotatable.
[0060] In this state, when the input shaft 22 is rotated by the
motor 21, the spline shaft drive gear 44 rotates, as a result,
shaft drive gear 46, the spline shaft 45, the spline nut 47, and
the pinion gear 48 rotates integrally. As the pinion gear 44
rotates, the rack 43 and the carry-in/out arm 12 move back and
forth integrally.
[0061] Thus, according to the pivoting/carry-in/out drive unit 15,
the pivoting of the pivoting frame 13 and the back and forth
movement of the carry-in/out arm 12 are driven by one motor 21 and
one planetary reduction gear 20.
[0062] Here, it is understood that the lifting frame 14 by the
lifting drive unit 16 can be performed simultaneously with the
pivoting of the pivoting frame 13 by the pivoting/carry-in/out
drive unit 15, and that the carrying-in/out arm 12 by the
pivoting/carry-in/out drive unit 15 is performed after the lifting
of the lifting frame 14 by the lifting drive unit 16 and the
pivoting of the pivoting frame 13 by the pivoting/carrying-in/out
drive unit 15 are completed.
[0063] According to the automatic pallet changer 2 described above,
it is possible to drive both the pivoting of the pivoting frame 13
and the back and forth movement of the carry-in/out arm 12 by using
one planetary reduction gear 20 and one motor 21 that drives the
planetary reduction gear 20. Therefore, compared to the
conventional automatic pallet changer that uses a motor for driving
the pivoting frame 13 and a motor for driving the back and forth
movement of the carry-in/out arm 12, it is possible to reduce the
size of the drive section and the motor servo amplifier.
[0064] According to the automatic pallet changer in the machine
tool of the present invention, one planetary reduction gear and one
motor that drives the planetary reduction gear can be used to drive
both horizontal movement of the horizontal movement frame and back
and forth movement of the carry-in/out arm, thereby miniaturization
and cost reduction can be achieved.
[0065] Although not shown, the above-described automatic pallet
changer can be applied to a system in which the pallet is linearly
arranged as well as carrying in/out the pallet by a stacker
crane.
[0066] In this way, a rack may be used instead of a fixed gear 19,
and a pinion gear that moves linearly along a rack may be used
instead of a pivoting gear 32, so that a straight moving frame in
place of a pivoting frame 13 is linearly moved.
REFERENCE SIGNS LIST
[0067] 1: machine tool body [0068] 2: automatic pallet changer
[0069] 11: pallet storage section [0070] 12: carry-in/out arm
[0071] 13: pivoting frame (horizontal moving frame) [0072] 14:
lifting frame [0073] 15: pivoting/carry-in/out drive unit [0074]
16: lifting drive unit [0075] 17: base frame [0076] 19: fixed gear
[0077] 20: planetary reduction gear [0078] 23: first fix]ing means
[0079] 24: second fixing means [0080] 25: first output shaft [0081]
26: second output shaft [0082] 27: Casing [0083] 32: pivoting gear
(first rotating gear) [0084] 43: rack [0085] 44: spline shaft drive
gear (second rotating gear) [0086] 45: spline shaft [0087] 46:
spline shaft driven gear (third rotating gear) [0088] 47: spline
nut [0089] 48: pinion gear [0090] 51: cylinder [0091] 52: piston
[0092] 53: piston fitting hole [0093] 54: cylinder [0094] 55:
piston [0095] 56: block [0096] 56a: piston inlet hole [0097] P:
pallet
* * * * *